A number of mature toolkits and language workbenches for DSL-based design have been proposed, making DSL-based design attractive for many projects. These toolkits preselect many architectural decision options. However, in many cases it would be beneficial for DSL-based design to decide for the DSL?s architecture later on in a DSL project, once the requirements and the domain have been sufficiently understood. We propose a language and a number of DSLs for DSL-based design and development that combine important benefits of different DSL toolkits in a unique way. Our approach specifically targets at deferring architectural decisions in DSL-based design. As a consequence, the architect can choose, even late in a DSL project, for options such as whether to provide the DSL as one or more external or embedded DSLs and whether to use an explicit language model or not